Enhanced Oil Recovery (EOR) may be used to increase oil recovery in fields worldwide. There are three main types of EOR, thermal, chemical/polymer and gas injection, which may be used to increase oil recovery from a reservoir, beyond what can be achieved by conventional means—possibly extending the life of a field and boosting the oil recovery factor.
Thermal enhanced recovery works by adding heat to the reservoir. The most widely practised form is a steamdrive, which reduces oil viscosity so that it can flow to the producing wells. Chemical flooding increases recovery by reducing the capillary forces that trap residual oil. Polymer flooding improves the sweep efficiency of injected water. Miscible injection works in a similar way to chemical flooding. By injecting a fluid that is miscible with the oil, trapped residual oil can be recovered.
Referring to FIG. 1, there is illustrated prior art system 100. System 100 includes underground formation 102, underground formation 104, underground formation 106, and underground formation 108. Production facility 110 is provided at the surface. Well 112 traverses formations 102 and 104, and terminates in formation 106. The portion of formation 106 is shown at 114. Oil and gas are produced from formation 106 through well 112, to production facility 110. Gas and liquid are separated from each other, gas is stored in gas storage 116 and liquid is stored in liquid storage 118.
U.S. Pat. No. 3,732,166 discloses Non-Newtonian formulations containing carbon disulfide (CS2) of reduced toxicity and flammability. These formulations are illustrated by high internal phase ratio (HIPR) emulsions containing carbon disulfide in the internal phase, said internal phase containing more than about 60% of the formulation by volume and preferably more than about 80% of the formulation by volume. These formulations are particularly useful in cleaning oil and gas wells by the removal of wax and/or sulfur. U.S. Pat. No. 3,732,166 is herein incorporated by reference in its entirety.
Co-pending U.S. Pat. No. 7,426,959, and having discloses a system including a mechanism for recovering oil and/or gas from an underground formation, the oil and/or gas comprising one or more sulfur compounds; a mechanism for converting at least a portion of the sulfur compounds from the recovered oil and/or gas into a carbon disulfide formulation; and a mechanism for releasing at least a portion of the carbon disulfide formulation into a formation. U.S. Pat. No. 7,426,959 which is herein incorporated by reference in its entirety.
U.S. Pat. No. 5,062,970 discloses a surfactant composition, suitable for enhanced oil recovery comprising in a 60:40 to 10/90 weight ratio a) (o,m)- and/or (o,p)-dialkylbenzene alkali sulfonate and b) polyalkoxyphenyl ether alkali sulfonate. U.S. Pat. No. 5,062,970 is herein incorporated by reference in its entirety.
Other compositions and methods for enhanced hydrocarbons recovery are described in U.S. Pat. No. 3,943,160; U.S. Pat. No. 3,946,812; U.S. Pat. No. 4,077,471; U.S. Pat. No. 4,216,079; U.S. Pat. No. 5,318,709; U.S. Pat. No. 5,723,423; U.S. Pat. No. 6,022,834; U.S. Pat. No. 6,269,881; and by Wellington, et al. in “Low Surfactant Concentration Enhanced Waterflooding,” Society of Petroleum Engineers, 1995; all of which are incorporated by reference herein.
There is a need in the art for improved systems and methods for enhanced oil recovery. There is a further need in the art for improved systems and methods for enhanced oil recovery using a solvent, for example through viscosity reduction, chemical effects, and miscible flooding. There is a further need in the art for improved systems and methods for solvent miscible flooding. There is a further need in the art for improved systems and methods for storing a solvent prior to and/or after miscible flooding. There is a further need in the art for improved systems and methods for transporting a solvent prior to and/or after miscible flooding.